Heat oil in a large skillet over medium-high heat.
Add the cubed chuck roast in batches, searing on all sides until browned. Transfer the browned beef directly to the slow cooker.
Add the sliced carrots and onions to the slow cooker.
In a medium bowl, whisk together brewed coffee, soy sauce, Worcestershire sauce, garlic powder, dried thyme, and black pepper. Pour the mixture over the beef and vegetables in the slow cooker.
Cover and cook on low for 5-6 hours or high for 3-4 hours, or until the roast is tender.
In a small bowl, whisk together cornstarch and cold water to create a slurry. Stir the slurry into the slow cooker, then cover and cook on high for 20-30 more minutes, or until the sauce has thickened.
Taste and adjust seasoning if needed. Serve hot, garnished with chopped parsley.